Symptoms of depression or anxiety were measured according to methods that included the Hospital Anxiety and Depression Scale (HADS), Beck Depression Inventory and the State-Trait Anxiety Index.

Among the IBS studies, six indicated either increased prevalence or higher scores for both depression and anxiety in patients with IBS compared with controls.

All Ulcerative Colitis studies found increased prevalence or score for anxiety among patients, while two also indicated increased depression prevalence or score.

Overall, patients with UC had either similar or greater degrees of psychological abnormalities compared with IBS patients. Depression was observed in 38% of IBS patients, while anxiety was present in 32%, compared with 50% and 64%, respectively, among those with UC. The mean HADS depression score for IBS patients was 5.4, compared with 4.1 among those with UC, while mean HADS anxiety scores were 8.1 and 8.5, respectively.

Eric D. Shah, MD, internal medicine resident at Cedars-Sinai Medical Center in Los Angeles, told Healio.com, “Just because patients with depression also happen to have IBS or vice versa, it’s not that one necessarily causes the other. We’ve seen that published in a lot of studies previously, that depression causes IBS, but we used UC as our negative control and saw even more in terms of prevalence, [and IBS] is similar to UC in terms of change to depression and anxiety scores. Based on existing data, we can’t say that depression causes IBS, but it’s still there; … we still see one-third of patients who have depression [or] anxiety.”